What happened
On August 5, 2013, at approximately 1800 Alaska daylight time, a Hughes 500D helicopter, registration N134SH, was performing a Part 133 external load flight near Delta Junction, Alaska. The pilot was using a 100-foot external load line attached to the belly-mounted cargo hook to transport sections of water hose to a remote location.
While the helicopter was hovering approximately 100 feet above the intended site and 5 to 10 feet above the tree canopy, the engine experienced a total loss of power. The pilot, facing into a hill, initiated an emergency hovering autorotation and turned the aircraft to the left to attempt to face downhill. During this maneuver, the helicopter settled into trees, causing the main rotor blades to strike several branches. The aircraft then impacted the terrain and rolled onto its right side. The accident resulted in no injuries, but the helicopter sustained substantial damage to the fuselage, tailboom, and main rotor drive system.
The investigation
Investigators examined the fuel system and found approximately 60 lbs of fuel in the fuel cell, of which 47 lbs were usable. Engine test-runs demonstrated that the engine produced full-rated power at various settings. Additionally, a test-run of the electric fuel pump showed it was operating within specifications, though examination of the pump revealed wear on the motor commutator and brushes. No mechanical malfunctions or failures were identified that would have prevented normal operation prior to the accident.